1. Field of the Invention
The present invention relates to a semiconductor device including a plurality of DMOS transistors and a method of manufacturing the same.
2. Description of the Related Art
DMOS (Double Diffused MOS) transistors are known which are mainly used as switching elements in high-voltage operating devices. DMOS transistors with a body layer on the source side being of a P-type are characterized in that they have an N+ diffusion layer of a high concentration in the P-type body layer. When a voltage is applied to the gate electrode of the DMOS transistor, part of the P-type body layer near the gate electrode is inverted, and a current flows from the source electrode to the drain electrode. Where the DMOS transistors are used in a high-voltage operating device such as a DC-DC converter or the like, the device is configured to have a plurality of DMOS transistors formed in parallel as shown in, e.g., Japanese Patent Kokai No. 2008-124396 (Patent Literature 1).